I have a Vitamin D deficiency but not B12 (I'm Vegan and take B12 supplements for years), been more exposed to sun lately so vitamin D is better

How is it related?

My nausea and throwing up calmed down, but I have this severe migraine that's killing me. I can only sit for small amount of time in front of my computer, I have to do lots of work on it, on word especially and reading articles.
I write on Word for 15 minutes and have to rest otherwise I feel bad again.

Pdoc doesn't think it's related to Lithium because it's 0.5 mmol/L - but sounds like lab's error because an increase of 300mg and after 1 week the level stays the same? doesn't make sense to me.

Besides it doesn't help generally. Maybe I should go back on Effexor XR, or just go off Lithium.

I'm so frustrated.